Door latch interlock system for microwave oven

Abstract

A door latch interlock system for use in a microwave oven in selectively securing a closure door in a closed position across the opening to the microwave oven cavity. The structure for selectively securing the door in the closed position includes a guide on the cabinet, a slider member movably carried by the guide, catch structure carried by the slider member, latch structure carried by the closure and engageable with the catch structure as an incident of the closure being disposed in the latching position, an actuator carried by the closure for operating one of the switches of the electrical circuit for controlling delivery of electric power to the microwave energy generator of the oven to permit operation of the generator only when the door is latched in the closed position, and manually operable structure carried by the closure for arranging the actuator to cause the one switch to prevent operation of the generator and concurrently move the slider member to the released disposition. A second switch control is carried by the latch structure for causing a second of the electrical circuit switches to prevent operation of the microwave energy generator whenever the closure door is in the closed position. In the illustrated embodiment, the guide is defined by a vertical support bar. The latch structure, in the illustrated embodiment, is defined by a pair of interconnected arms pivoted from the support bar. In the illustrated embodiment, the slider member is biased upwardly to the latching position. In the illustrated embodiment, the manually operable structure includes a pushbutton connected to the door handle.

We claim: 
     
       1. In a microwave oven having a cabinet defining an oven cavity provided with an opening, a closure movably mounted to said cabinet for movement between a closed position closing said opening and an open position providing access to said opening, electrically operable microwave energy generating means for supplying microwave energy to said cavity, and an electrical circuit including switch means for controlling delivery of electric power from an external source to said generating means, improved means for selectively securing said closure in a closed position wherein the closure sealingly closes said opening automatically as an incident of the closure being moved to said closed position comprising: a slider member movably mounted to said cabinet for movement between released and latching positions;   catch means movable with said slider member;   means for biasing said slider member toward the latching position at all times;   latch means carried by said closure and engageable with said catch means for automatically latching said closure in the closed position as an incident of said closure being moved to said closed position with said slider member being disposed in said latching position;   actuator means for operating said switch means to permit operation of said generating means only when said closure is latched in said closed position; and   manually operable means for arranging said actuator means to cause said switch means to prevent operation of the generating means and concurrently move said slider member to said released position for unlatching said closure while in said closed position and thereby permitting said unlatched closure to be moved selectively from said closed position to said open position.   
     
     
       2. The microwave oven structure of claim 1 wherein said switch means include first and second switches for controlling provision of electrical power to said generating means, and said latch means includes means for causing said second switch to close for permitting operation of the generating means only when the closure is in said closed position. 
     
     
       3. The microwave oven structure of claim 1 wherein said manually operable means includes a pushbutton mechanism carried by said closure. 
     
     
       4. The microwave oven structure of claim 1 wherein said manually operable means includes a pushbutton mechanism carried by said closure and means for biasing said pushbutton mechanism to arrange said actuator means to cause said switch means to permit energization of said generating means only when the closure is latched in the closed position. 
     
     
       5. In a microwave oven having a cabinet defining an oven cavity provided with an opening, a closure mounted to said cabinet for movement between a closed position closing said opening and an open position providing access to said opening, electrically operable microwave energy generating means for supplying microwave energy to said cavity, and an electrical circuit including a plurality of switches carried by said cabinet for controlling delivery of electric power from an external source to said generating means, improved means for selectively securing said closure in a closed position wherein the closure sealingly closes said opening comprising: a guide on said cabinet;   a slider member movably carried by said guide for movement between released and latching positions;   catch means carried by said slider member;   means for biasing said slider member toward the latching position at all times;   latch means carried by said closure and engageable with said catch means to latch the closure in the closed position as an incident of said closure being moved to said closed position with said slider member being disposed in said latching position;   actuator means carried by said closure for operating one of said switches to permit operation of said generating means only when said closure is latched in said closed position;   manually operable means carried by said closure for arranging said actuator means to cause said one switch to prevent operation of the generating means and concurrently move said slider member to said released position against the action of said biasing means for unlatching said latch means from said catch means with said closure disposed in said closed position, thereby permitting the unlatched closure to be moved selectively from said closed position to said open position; and   means carried by said latch means for causing a second of said switches to permit operation of said generating means only when the closure is in the closed position.   
     
     
       6. The microwave oven structure of claim 5 wherein said catch means comprises a pin fixedly carried by said slider member. 
     
     
       7. The microwave oven structure of claim 5 wherein said actuator means comprises a first portion engageable with said slider member to disengage said catch means from said latch means in the closed position of the closure, and a second portion defining an actuator for actuating said one switch. 
     
     
       8. The microwave oven structure of claim 5 wherein said means carried by the latch means comprises an integral distal end portion of the latch means. 
     
     
       9. The microwave oven structure of claim 5 wherein said latch means further defines cam means for urging the catch means to move the slider member toward said released position. 
     
     
       10. The microwave oven structure of claim 5 wherein said actuator means and manually operable means comprise a first pivot member pivotally carried by the closure and releasably engaging said slider member, a second pivot member pivotally carried by the closure releasably engaging said one switch, and manipulatable means carried by the closure for pivoting the pivot members. 
     
     
       11. The microwave oven structure of claim 5 wherein said actuator means and manually operable means comprise a first pivot member pivotally carried by the closure and releasably engaging said slider member, a second pivot member pivotally carried by the closure releasably engaging said one switch, means for pivoting said second pivot member as a result of pivoting of the first pivot member, and manipulatable means carried by the closure for pivoting the pivot members. 
     
     
       12. In a microwave oven having a cabinet defining a cavity having an access opening, a closure for selectively sealingly closing said opening having a handle thereon, and microwave generating means for producing microwave energy within said cavity, means for releasably securing said closure in the closed position and concurrently electrically connecting said generating means to a source of electrical potential comprising: a vertical support extending along an edge of said closure, said support having horizontal extending arms fixed thereon, each of said arms having vertically downwardly extending fingers at a distal end;   a pair of interconnected arms pivoted from said support in vertically spaced relationship to each other, said pivoted arms extending horizontally from said support, a lower of said pivoted arms having a downwardly extending finger thereon:   a vertically disposed guide channel within said cabinet having an upwardly biased slide channel positioned for vertical reciprocating movement therein, said guide channel and said slide channel having aligned apertures for receiving said arms when said closure is in said closed position, said slide channel having horizontal pins mating in locking relationship with said fingers on said fixed arms when said closure is in said sealing relationship, said guide channel having a secondary switch and a monitor switch mounted thereon engaged by said fixed arms and operated to an "on" position of said generating means when said closure is moved to said sealing relationship;   a guide roller on said slide channel operable when said pins move to lock the fixed arms to bear against and pivot an upper of the pivoted arms, said pivot movement operating through said interconnection to rotate said lower pivoted arm to bring said finger on said lower pivoted arm into moving contact with a primary interlock switch, said moving contact closing said switch; and   pushbutton means connected to said closure handle for freeing said pins from said fixed arm fingers and for removing said lower pivoted arm contact from said primary interlock switch, said button means being inwardly movable to bear against a vertical portion of the upper pivoted arm to pivot said upper pivoted arm against said roller to move said slide channel downwardly releasing said pins from said fixed arm fingers, whereby an outward force applied to said closure handle after pushing said pushbutton means will allow movement of said door out from said closed position and concurrently cause said monitor and secondary switches to be in an "off" condition to de-energize said generating means.   
     
     
       13. The microwave oven structure of claim 12 wherein said vertical support comprises a bar carried by the closure. 
     
     
       14. The microwave oven structure of claim 12 wherein said closure comprises a door pivotally mounted to said cabinet for horizontal swinging movement. 
     
     
       15. The microwave oven structure of claim 12 wherein said fixed arms are formed integrally with said support. 
     
     
       16. The microwave oven structure of claim 12 wherein said pivoted arms are interconnected by cooperating pin and link means. 
     
     
       17. The microwave oven structure of claim 12 wherein toggle means are provided for selectively retaining said pivoted arms in oppositely thrown dispositions. 
     
     
       18. The microwave oven structure of claim 12 wherein biasing means are provided for biasing said pushbutton means to an outward, released disposition.